The present invention relates to sugarless and sugar containing gums, including chewing gums and bubble gums, and more particularly to gum compositions substantially free from water and having desirable resistance to moisture pick up.
Conventional chewing gum process steps disclosed in the prior art involve cooling, extruding and forming into gum pieces, the formulated chewing gum composition. The formed gum must then be conditioned (setting) for 24-48 hours. Additionally, if the chewing gum is to be a hard sugar-coated gum piece (e.g., a pellet or ball), usually 48 hours of conditioning at 66.degree.-70.degree.F./RH 47-55% is required prior to the application of the coating. It is traditionally necessary to apply the coating under controlled temperature conditions (80.degree.-85.degree. F.) at low relative humidity (RH 24-40%). These conditions must be maintained closely or serious processing problems can result. For example, changes in the temperature and humidity outside of these ranges cause softening of the gum and deformation of shape which makes coating difficult. The problem has been well-known for many years and is especially harmful in areas with extreme climates such as the tropics. If the chewing gum is formed as a slab or stick gum, one prior art method required immediately wrapping the gum subsequent to 24-48 hour conditioning in order that the gum product would retain its freshness.
Additionally, conventional gum processes, which used traditional high speed wrapping machines (e g., 800-1800 sticks or slabs per minute), require the wrapping to be done at controlled temperature and humidity conditions. If the temperature or humidity became too high, the chewing gum composition would stick to the rollers and cutters. The individual gum pieces would be wrapped in airtight packages and usually those would be placed in larger boxes which themselves would be sealed to keep out air and moisture. In spite of all these precautions during processing, conventional chewing gum tends to stick to wrappers at high temperatures and to become brittle at low temperatures during storage. Additionally, conventional mint flavored chewing gum and some fruit flavors undergo oxidation of the flavors due to the interaction of the flavor with the base in the presence of moisture.
Conventional chewing gum formulations generally have a molten chewing gum base, resins, waxes, fillers, emulsifiers, an aqueous sugar syrup (corn syrup or sorbitol syrup), dry sugar (sucrose or dextrose) and flavor. The aqueous sugar syrup or non-sugar syrup has always been believed to be a necessary component as far as conventional commercial manufacture is concerned. As a result, the chewing gum product would ordinarily contain 2% to 8% by weight of moisture. As time passes, conventional products harden and become brittle as the sugar syrup crystallizes and excludes water. Ingredients such as humectants are employed to retard crystallization by retaining water. Not only is this protection temporary at best, compositions containing humectants tend to pick up moisture, resulting in processing difficulties and moisture-related product degradation.
Moisture related product degradation is one of the prime stability concerns for chewing gum compositions and products. The environmental factor influencing moisture loss or gain is relative humidity. It is commonly accepted that the lower the relative humidity, the faster things dry out. Relative humidity (RH) is a measure of the vapor pressure exerted by the moisture in the atmosphere. As relative humidity increases or decreases, the pressure of the moisture in the atmosphere increases or decreases accordingly. Pure water exerts a moisture vapor pressure equal to 100% RH. As such, that water will evaporate when stored in any environment less than 100% RH. If impurities are added to that water, the moisture vapor pressure will decrease.
Equilibrium relative humidity (ERH) is a means of identifying the susceptibility or propensity of the composition to moisture gain or loss, which in turn relates to the tendency for the gum to remain moisture stable and to not dry out or become stale, or pick up moisture and degrade. When the product neither picks up or loses moisture, it is in a state of equilibrium with the environment. The ERH measurement depends on the ratio of free moisture to bound moisture in a product and the temperature. The amount and rate at which a chewing gum loses or gains moisture depends on the differential between the product's ERH and ambient RH. The transfer of moisture will be in the direction from high to low RH until an equilibrium state is reached.
The prior art has addressed the problem of crystallization with low-moisture products that do not exclude water and harden when exposed to conditions of RH lower than ERH. U.S. Pat. No. 4,514,422 discloses a composition with less than 2% moisture derived from the use of 10% to 18% by weight of glycerin, a humectant, as a softener. However, the composition has an ERH less than 25% and is susceptible to moisture gain, and the problems related therewith, when the RH exceeds this.
Chewing gum compositions are known using propylene glycol in combination with glycerin at levels between 10% to 18% by weight. While this results in a composition with a higher ERH, the product is still susceptible to moisture gain and moisture gain related problems.
U.S. Pat. No. 4,581,234 discloses a composition with less than 0.3% moisture and resistant to moisture gain up to 80% RH. However, critical to the function of this product is the use of a soft gum base, defined as having a softening point between about 40.degree. C. and about 60.degree. C. Chewing gum compositions resistant to hardening and moisture gain having formulations in which the choice of gum base softening point is not critical would be highly desirable.
U.S. Pat. No. 4,753,806 discloses a composition with 2 to 8% moisture and relatively high ERH formulated with aqueous hydrogenated starch hydrolysate cooked to a moisture content of 4 to 12% and 0 to 12% glycerin.
The present invention concerns chewing gum compositions which, unlike those of the prior art, can be processed using fewer steps, thereby saving time and production costs. The process of the present invention does not require such traditional process steps as cooling and conditioning (setting), nor does it require specified relative humidity conditions for coated gums, as does the prior art. Additionally, no protective wrapping is necessary to maintain freshness. The compositions of the present invention do not require one or more moisture containing additives, nor a soft gum base, in order to obtain a formulation of viscosity which is manageable and homogeneous, and which ultimately yields a chewing gum product which has good texture, mouthfeel and/or organoleptic properties. The present compositions, when prepared in the specified manner, have the juiciness, flavor, texture, mouthfeel and other organoleptic characteristics of known compositions which use moisture or moisture containing ingredients to achieve these characteristics.
Another advantage of the instant invention is that those ingredients which are ordinarily unstable in the presence of moisture, e.g., aspartame, do not present a problem since the inventive compositions are substantially anhydrous. Thus, traditionally moisture unstable ingredients can be added and without fear of deterioration or instability.
Another advantage to the instant invention is that the gum product formed from the disclosed compositions and using the disclosed method can be wrapped immediately after forming without the need for conventional cooling followed by conditioning for 24-48 hours. The inventive compositions can be wrapped immediately within 2 hours of rolling without fear of wrapping materials adhering to the chewing gum product.
Another advantage of the instant invention is that chewing gum products formed by means of the disclosed process and containing the disclosed compositions can remain without wrapping or protective covering at ambient temperatures for longer periods of time than traditional chewing gums without going stale, becoming tacky or showing instability. Thus, the inventive compositions retain their freshness for up to a year or more without the need for protective, hermetic wrappings.
As stated above, the inventive process does not require all of the process steps of the prior art. The chewing gum compositions once formed do not have to be cooled prior to formation into gum pieces, nor conditioned prior to wrapping. These advantages are due to the specific and novel formulations presented herein.
Other advantages of the present compositions and process of preparation will become apparent from the detailed description provided herein.